National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 021558
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1058 AM EST MON DEC 2 2013

.SYNOPSIS...
-- Changed Discussion --
LOW PRESSURE DEVELOPING OFF THE CAROLINA COAST TODAY WILL TRACK
FARTHER OFFSHORE THROUGH TUESDAY. A WEAK AREA OF HIGH PRESSURE
WILL BUILD OVER THE AREA BRIEFLY DURING MIDWEEK BEFORE A COLD
FRONT GRADUALLY MOVES THROUGH LATE IN THE WEEK. HIGH PRESSURE
WILL BRIEFLY BUILD OVERHEAD TO START THE WEEKEND...BUT LOW
PRESSURE MAY IMPACT THE AREA LATE SUNDAY INTO EARLY NEXT WEEK.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
15Z SFC ANALYSIS SHOWS A WEAK SFC LOW OVER SERN ONTARIO WITH A COLD
FRONT STRETCHING SEWD ACROSS THE OH VLY. FARTHER DOWNSTREAM...THE
CENTER OF A DEVELOPING COASTAL LOW IS LOCATED ABOUT 150 MILES OFF
THE SC COAST.

AN AREA OF SUBSIDENCE ON THE NRN PERIPHERY OF THE DEVELOPING COASTAL
LOW HAS RESULTED IN A NARROW BELT OF CLEARING AS FAR NORTH AS LWR
SRN MD. THERE IS STILL SOME UNCERTAINTY WITH HOW FAR NORTH THE
CLEARING WILL MAKE IT...BUT THIS WILL IMPACT TEMPS TDA WITH
LOCATIONS TO THE NORTH AND WEST OF THIS CLEARING LINE REMAINING
COOLER AND SOCKED IN CLOUDS. MAX TEMPS GENERALLY IN THE 40S TDA
THOUGH AREAS IN SRN MD AND THE NRN PIEDMONT THAT EXPERIENCE MORE
CLEARING TDA WILL HAVE THE POTENTIAL TO REACH THE LOWER 50S.

THE COLD FRONT TO OUR NW WILL DISSIPATE OVER THE OH VLY TNGT WHILE
THE COASTAL LOW TRACKS NEWD AND AWAY FROM THE MID-ATLANTIC COAST.
MEANWHILE...AN UPPER-LEVEL JET STREAK IS EXPECTED TO STRENGTHEN
AS IT ENTERS THE CENTRAL CONUS. A PIECE OF THE SHORTWAVE ENERGY
FROM THIS SYSTEM WILL EJECT TOWARD THE CENTRAL APPALACHIANS LATE
TNGT...WHICH COULD RESULT IN SOME LGT SHOWERS OR SPRINKLES
BREAKING OUT ACROSS THE POTOMAC HIGHLANDS DURING THE NGT. SOME OF
THIS ACTIVITY MAY MIX WITH SNOW TOWARD THE ALLEGHENY FRONT...BUT
NO ACCUM IS FCST. OTHERWISE THE CWA SHOULD BE DRY DURING THE
PERIOD WITH THE CWA SITUATED IN BETWEEN BOTH OF THE
AFOREMENTIONED SFC FEATURES.
-- End Changed Discussion --




&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
SURFACE HIGH PRESSURE WILL BUILD OVERHEAD TUESDAY BEFORE MOVING OFF
THE COAST TUESDAY NIGHT AND WEDNESDAY. SKIES WILL TURN OUT PARTLY TO
MOSTLY CLOUDY TUESDAY DUE TO SOME LOW CLOUDS TRAPPED UNDERNEATH THE
SUBSIDENCE INVERSION. MAX TEMPS TUESDAY WILL BE NEAR CLIMO...RANGING
FROM THE 40S IN THE MOUNTAINS TO THE LOWER AND MIDDLE 50S ACROSS
MOST OTHER LOCATIONS.

AS HIGH PRESSURE MOVES OFF THE COAST TUESDAY NIGHT AND WEDNESDAY...A
RETURN FLOW WILL DEVELOP. MORE LOW CLOUDS ARE EXPECTED AND THERE
WILL ALSO BE HIGH/MID CLOUDS DUE TO SHORTWAVE ENERGY IN THE ZONAL FLOW
ALOFT. THEREFORE...SKIES WILL TURN OUT CLOUDY/MOSTLY CLOUDY. DESPITE
THE CLOUD COVER...SOUTHERLY WINDS WILL ALLOW FOR MILD CONDITIONS FOR
THIS TIME OF YEAR.
-- End Changed Discussion --

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --
AN UPPER-LEVEL TROUGH WILL REMAIN OVER THE ROCKIES WEDNESDAY
NIGHT THROUGH SUNDAY WHILE THE SUBTROPICAL RIDGE STRENGTHENS OVER
THE SOUTHEASTERN CONUS. A SOUTHWEST FLOW IS EXPECTED ALOFT IN
BETWEEN THESE SYSTEMS ACROSS OUR AREA.

LOW PRESSURE WILL TRACK FROM THE GREAT LAKES INTO CANADA WEDNESDAY
NIGHT AND THURSDAY WHILE THE COLD FRONT ASSOCIATED WITH THIS LOW
SLOWLY APPROACHES FROM THE NORTHWEST. THE COLD FRONT WILL BE SLOW TO
PASS THROUGH OUR REGION LATE IN THE WEEK DUE TO THE SOUTHWEST FLOW
ALOFT. PERIODS OF RAIN ARE EXPECTED DURING THIS TIME AS THE FRONT
SLOWLY PASSES THROUGH. TIMING DETAILS ARE STILL UNCERTAIN AT THIS
TIME...BUT AS OF NOW IT APPEARS THAT THE BEST CHANCE FOR
PRECIPITATION WILL BE THURSDAY NIGHT THROUGH FRIDAY NIGHT.

RAIN MAY END AS A LITTLE SNOW FRIDAY NIGHT INTO SATURDAY AS COLD AIR
WORKS ITS WAY IN BEHIND THE FRONT. THE BEST CHANCE FOR ANY SNOW WILL
BE IN THE MOUNTAINS.

HIGH PRESSURE WILL RETURN BRIEFLY LATE SATURDAY INTO SUNDAY BEFORE
ANOTHER STORM SYSTEM POSSIBLY IMPACTS THE AREA EARLY NEXT WEEK.
THERE MAY BE ENOUGH COLD AIR ASSOCIATED WITH THIS STORM FOR WINTRY
PRECIPITATION.
-- End Changed Discussion --

&&

.AVIATION /16Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
OVC CIGS BETWEEN 5-7 KFT TDA AND TNGT. SOME HZ IS BEING OBSERVED
EAST OF THE BLUE RIDGE THIS MRNG UNDER THE INFLUENCE OF WEAK
HIPRES AND A LGT WIND FIELD. A BRIEF SHRA OR SPRINKLE POSSIBLE
TNGT AT MRB. MODEL GUIDANCE INDICATE REDUCED VSBYS WITH FOG TNGT
BUT THINK THE POTENTIAL IS LIMITED BY THE CLOUD COVER OVER THE
AREA. KEPT VSBYS IN MVFR/VFR RANGE.

HIGH PRESSURE WILL BUILD OVERHEAD TUESDAY BEFORE MOVING OFF THE
COAST TUESDAY NIGHT AND WEDNESDAY. A RETURN FLOW WILL CAUSE LOWERING
CIGS TUESDAY NIGHT. IFR CONDITIONS ARE POSSIBLE OVERNIGHT TUESDAY
INTO WEDNESDAY. CIGS MAY BE SLOW TO IMPROVE WEDNESDAY. MORE IFR
CONDITIONS ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY AS A WARM
FRONT MOVES THROUGH. A COLD FRONT WILL SLOWLY PASS THROUGH THE
TERMINALS LATE IN THE WEEK. SUBVFR CIGS/VSBYS ARE POSSIBLE ALONG
WITH PERIODS OF RAIN.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
LGT ELY WINDS AROUND 5 KT TDA WILL BECOME NLY BETWEEN 5-10 KT LATE
TNGT AS LOPRES TRACKS NEWD AND WELL OFF THE MID-ATLANTIC COAST.

HIGH PRESSURE OVER THE WATERS TUESDAY WILL MOVE OFF SHORE WEDNESDAY.
A COLD FRONT WILL APPROACH THURSDAY BEFORE PASSING THROUGH LATE IN
THE WEEK. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE
WATERS AHEAD OF THE FRONT LATE IN THE WEEK AND BEHIND THE FRONT
SATURDAY.
-- End Changed Discussion --

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
UPDATE...JRK
PREV DISC...WOODY!/BJL